The natural history of Diabetic Angiopathy is poorly understood, because the traditional methods of studying arterial stenosis involve the use of contrast radiography which carries a significant risk, and can therefore not be used in serial prospective studies in normal subjects. This project uses a series of non-invasive techniques to evaluate the patency of peripheral arteries. More than 500 unselected diabetics are being recruited from the Seattle area. Each of these will be studied for a period of five years, visiting the laboratory every year or every six months if arterial disease is found. On yearly visits, the subject will have blood drawn for a lipid classification and an electrolyte screen. On each visit, the subject will have a medical history taken, a physical examination, and a vascular laboratory examination, including oculoplethysmography, supraorbital photoplethysmography, carotid and supraorbital doppler velocimetry, digital plethysmography, brachial, femoral, posterior tibial and dorsalis pedis doppler velocimetry, and pre- and post-exercise segmental leg blood pressure. The laboratory studies allow a complete evaluation of the dynamic status of the subject's arterial tree. The arterial status and the serial change in status over the five year period will be correlated with the subject's lifestyle and health factors. It is hoped that the diabetic population will be compared with a set of controls drawn from the local Lipid Research Center study.